Universal are literally in the process of creating a villains land of their own at Epic Universe with Classic Monsters. I think an important key to making a villains land work well is variety. Universal isn't centering their land on a singular monster from what I gather, but a variety of different ones.
And mind you, Universal already did dabble in a villains area with Knockturn Alley. Albeit as a sub section of a larger land. And I think there are plenty of people who would like more of that.
But again regarding variety. Voldemort is just one single villain from a single story. To make matters worse, there's not really a singular iconic "lair" setting that i'd associate him with. The Malfoy Manor is the closest thing that might come to mind, but it's a temporary base that isn't really his own. Not only are there a ton of Disney villains to draw from, most of their lairs are also varied and interesting. Same goes for Classic Monsters.
Given their trends in recent attractions and animated films, I just don't think Disney is interested in the classic "evil and loving it" villains anymore. Tiana's Bayou Adventure won't have a villain. Tokyo's BATB ride relegated Gaston and the mob to shadow projections shoved into a background wall (and it was a movie that already diverged somewhat from a traditional villain). And they heavily reduced the scares and witch appearances (and removed all the skeletons) from Snow White at DL.